About Sleep Apnea

Sleep apnea is a chronic disorder that affects millions of people worldwide. Apnea is defined as the cessation of breathing for a period of 10 seconds or longer (Des & Burton, 1995, p.415). When airflow is not completely obstructed, but is decreased by 30% or greater and is accompanied with an oxygen desaturation of at least 4%, a hypopnea is recorded. The sum of apnea and hypopnea events is termed Apnea-Hypopnea Index, or AHI and is used to score the severity of sleep apnea. An AHI less than 5 doesn't signify a sleep disorder diagnosis. There are three categories of sleep apnea: obstructive, central,and mixed (Hess, 2012, p.957).

Obstructive Sleep Apnea (OSA) is the most commonly diagnosed disorder (Des & Burton, 1995, p.416). With obstructive sleep apnea, the cessation of breathing is caused by an anatomic obstruction of the upper airway with the continuation of ventilatory effort, characterized by chest and abdominal movement throughout the apneic period (Des & Burton, 1995; Hess, 2012). Males are more likely to be diagnosed with OSA, and it is especially common in middle-aged men. OSA is also prevalent in obese persons and those with large neck circumference (Des & Burton, 1995, p.416).

Central Sleep Apnea (CSA) is characterized by the cessation of airflow and ventilatory effort. CSA occurs when the respiratory centers of the brain neglects to transmit proper signals to the ventilatory muscles. CSA is infrequently diagnosed, but is may occur because of other conditions, such as heart failure, stroke, brain stem disorders, and cervical cordotomy, as well as many other clinical disorders (Des& Burton, 1995; Hess, 2012; & Mayo Clinic, 2016).

Mixed Sleep Apnea, often referred to complex sleep apnea is a combination of characteristics of obstructive and central sleep apneas. Central apneas characteristically initiate apneic episodes followed by the onset of obstructive apneas (Des & Burton, 1995; Hess, 2012). Mixed apneas are frequently treated with positive pressure ventilation (Des & Burton, 1995, p.417).